1. Field of the Invention
This invention relates generally to bicycles and more particularly to bicycle seat posts and mechanisms for clamping a bicycle seat to a seat post.
2. Description of the Related Art
It is well known that conventional bicycles have frames made, at least in part, of tubular material. The central tube of the typical bicycle frame, which is a hollow tube with at least the upper end open to permit insertion of a seat post, is referred to as the “seat tube”. In a typical bicycle, therefore, a bicycle seat (also called a “saddle”) is mounted to the top of a seat post, typically by a clamping mechanism that is attached to the upper end of the seat post, and the bottom end of the seat post is inserted into the seat tube of the frame.
Conventional seat clamping mechanisms are made of heavy metal, such as steel, in order to be strong enough to support the forces applied to the clamp by the seat rails. The substantial forces applied to the clamp arise from the common construction of bicycle seats. Standard bicycle seat rails extend from the narrow front of the seat to the wider back of the seat and are 7.0 mm diameter rods, typically made of steel or a lightweight alloy such as titanium. Each rail is held tightly about mid way along its length in the clamp to transfer the weight of the rider from the upper surface of the seat, upon which the rider sits, to the clamp, which is mounted to the seat post. The clamp must also prevent the seat from coming off the bicycle under extreme side and upwardly directed forces that can be applied to the seat. The forces applied by the rails on the seat post clamp can be enormous due to the small contact area and the substantial weight of some riders.
Conventional clamping mechanisms are also typically mounted to the seat posts by insertion to the upper end thereof. This results in a weak joint that can be broken by stresses that are often encountered on bicycle seat posts. In order to overcome these weaknesses, heavier seat posts have been used. But there is a need for less weight on bicycles, and therefore existing seat posts are not satisfactory.